﻿// Copyright (c) All contributors. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

using System;
using System.Linq;
using MessagePack;
using Xunit;

public class SipHashTests
{
    // Test battery taken from: https://github.com/veorq/SipHash/blob/master/main.c
    private static readonly uint[][] Vectors = new[]
    {
        new uint[] { 0x31, 0x0e, 0x0e, 0xdd, 0x47, 0xdb, 0x6f, 0x72 },
        new uint[] { 0xfd, 0x67, 0xdc, 0x93, 0xc5, 0x39, 0xf8, 0x74 },
        new uint[] { 0x5a, 0x4f, 0xa9, 0xd9, 0x09, 0x80, 0x6c, 0x0d },
        new uint[] { 0x2d, 0x7e, 0xfb, 0xd7, 0x96, 0x66, 0x67, 0x85 },
        new uint[] { 0xb7, 0x87, 0x71, 0x27, 0xe0, 0x94, 0x27, 0xcf },
        new uint[] { 0x8d, 0xa6, 0x99, 0xcd, 0x64, 0x55, 0x76, 0x18 },
        new uint[] { 0xce, 0xe3, 0xfe, 0x58, 0x6e, 0x46, 0xc9, 0xcb },
        new uint[] { 0x37, 0xd1, 0x01, 0x8b, 0xf5, 0x00, 0x02, 0xab },
        new uint[] { 0x62, 0x24, 0x93, 0x9a, 0x79, 0xf5, 0xf5, 0x93 },
        new uint[] { 0xb0, 0xe4, 0xa9, 0x0b, 0xdf, 0x82, 0x00, 0x9e },
        new uint[] { 0xf3, 0xb9, 0xdd, 0x94, 0xc5, 0xbb, 0x5d, 0x7a },
        new uint[] { 0xa7, 0xad, 0x6b, 0x22, 0x46, 0x2f, 0xb3, 0xf4 },
        new uint[] { 0xfb, 0xe5, 0x0e, 0x86, 0xbc, 0x8f, 0x1e, 0x75 },
        new uint[] { 0x90, 0x3d, 0x84, 0xc0, 0x27, 0x56, 0xea, 0x14 },
        new uint[] { 0xee, 0xf2, 0x7a, 0x8e, 0x90, 0xca, 0x23, 0xf7 },
        new uint[] { 0xe5, 0x45, 0xbe, 0x49, 0x61, 0xca, 0x29, 0xa1 },
        new uint[] { 0xdb, 0x9b, 0xc2, 0x57, 0x7f, 0xcc, 0x2a, 0x3f },
        new uint[] { 0x94, 0x47, 0xbe, 0x2c, 0xf5, 0xe9, 0x9a, 0x69 },
        new uint[] { 0x9c, 0xd3, 0x8d, 0x96, 0xf0, 0xb3, 0xc1, 0x4b },
        new uint[] { 0xbd, 0x61, 0x79, 0xa7, 0x1d, 0xc9, 0x6d, 0xbb },
        new uint[] { 0x98, 0xee, 0xa2, 0x1a, 0xf2, 0x5c, 0xd6, 0xbe },
        new uint[] { 0xc7, 0x67, 0x3b, 0x2e, 0xb0, 0xcb, 0xf2, 0xd0 },
        new uint[] { 0x88, 0x3e, 0xa3, 0xe3, 0x95, 0x67, 0x53, 0x93 },
        new uint[] { 0xc8, 0xce, 0x5c, 0xcd, 0x8c, 0x03, 0x0c, 0xa8 },
        new uint[] { 0x94, 0xaf, 0x49, 0xf6, 0xc6, 0x50, 0xad, 0xb8 },
        new uint[] { 0xea, 0xb8, 0x85, 0x8a, 0xde, 0x92, 0xe1, 0xbc },
        new uint[] { 0xf3, 0x15, 0xbb, 0x5b, 0xb8, 0x35, 0xd8, 0x17 },
        new uint[] { 0xad, 0xcf, 0x6b, 0x07, 0x63, 0x61, 0x2e, 0x2f },
        new uint[] { 0xa5, 0xc9, 0x1d, 0xa7, 0xac, 0xaa, 0x4d, 0xde },
        new uint[] { 0x71, 0x65, 0x95, 0x87, 0x66, 0x50, 0xa2, 0xa6 },
        new uint[] { 0x28, 0xef, 0x49, 0x5c, 0x53, 0xa3, 0x87, 0xad },
        new uint[] { 0x42, 0xc3, 0x41, 0xd8, 0xfa, 0x92, 0xd8, 0x32 },
        new uint[] { 0xce, 0x7c, 0xf2, 0x72, 0x2f, 0x51, 0x27, 0x71 },
        new uint[] { 0xe3, 0x78, 0x59, 0xf9, 0x46, 0x23, 0xf3, 0xa7 },
        new uint[] { 0x38, 0x12, 0x05, 0xbb, 0x1a, 0xb0, 0xe0, 0x12 },
        new uint[] { 0xae, 0x97, 0xa1, 0x0f, 0xd4, 0x34, 0xe0, 0x15 },
        new uint[] { 0xb4, 0xa3, 0x15, 0x08, 0xbe, 0xff, 0x4d, 0x31 },
        new uint[] { 0x81, 0x39, 0x62, 0x29, 0xf0, 0x90, 0x79, 0x02 },
        new uint[] { 0x4d, 0x0c, 0xf4, 0x9e, 0xe5, 0xd4, 0xdc, 0xca },
        new uint[] { 0x5c, 0x73, 0x33, 0x6a, 0x76, 0xd8, 0xbf, 0x9a },
        new uint[] { 0xd0, 0xa7, 0x04, 0x53, 0x6b, 0xa9, 0x3e, 0x0e },
        new uint[] { 0x92, 0x59, 0x58, 0xfc, 0xd6, 0x42, 0x0c, 0xad },
        new uint[] { 0xa9, 0x15, 0xc2, 0x9b, 0xc8, 0x06, 0x73, 0x18 },
        new uint[] { 0x95, 0x2b, 0x79, 0xf3, 0xbc, 0x0a, 0xa6, 0xd4 },
        new uint[] { 0xf2, 0x1d, 0xf2, 0xe4, 0x1d, 0x45, 0x35, 0xf9 },
        new uint[] { 0x87, 0x57, 0x75, 0x19, 0x04, 0x8f, 0x53, 0xa9 },
        new uint[] { 0x10, 0xa5, 0x6c, 0xf5, 0xdf, 0xcd, 0x9a, 0xdb },
        new uint[] { 0xeb, 0x75, 0x09, 0x5c, 0xcd, 0x98, 0x6c, 0xd0 },
        new uint[] { 0x51, 0xa9, 0xcb, 0x9e, 0xcb, 0xa3, 0x12, 0xe6 },
        new uint[] { 0x96, 0xaf, 0xad, 0xfc, 0x2c, 0xe6, 0x66, 0xc7 },
        new uint[] { 0x72, 0xfe, 0x52, 0x97, 0x5a, 0x43, 0x64, 0xee },
        new uint[] { 0x5a, 0x16, 0x45, 0xb2, 0x76, 0xd5, 0x92, 0xa1 },
        new uint[] { 0xb2, 0x74, 0xcb, 0x8e, 0xbf, 0x87, 0x87, 0x0a },
        new uint[] { 0x6f, 0x9b, 0xb4, 0x20, 0x3d, 0xe7, 0xb3, 0x81 },
        new uint[] { 0xea, 0xec, 0xb2, 0xa3, 0x0b, 0x22, 0xa8, 0x7f },
        new uint[] { 0x99, 0x24, 0xa4, 0x3c, 0xc1, 0x31, 0x57, 0x24 },
        new uint[] { 0xbd, 0x83, 0x8d, 0x3a, 0xaf, 0xbf, 0x8d, 0xb7 },
        new uint[] { 0x0b, 0x1a, 0x2a, 0x32, 0x65, 0xd5, 0x1a, 0xea },
        new uint[] { 0x13, 0x50, 0x79, 0xa3, 0x23, 0x1c, 0xe6, 0x60 },
        new uint[] { 0x93, 0x2b, 0x28, 0x46, 0xe4, 0xd7, 0x06, 0x66 },
        new uint[] { 0xe1, 0x91, 0x5f, 0x5c, 0xb1, 0xec, 0xa4, 0x6c },
        new uint[] { 0xf3, 0x25, 0x96, 0x5c, 0xa1, 0x6d, 0x62, 0x9f },
        new uint[] { 0x57, 0x5f, 0xf2, 0x8e, 0x60, 0x38, 0x1b, 0xe5 },
        new uint[] { 0x72, 0x45, 0x06, 0xeb, 0x4c, 0x32, 0x8a, 0x95 },
    };

    [Fact]
    public void TestBattery_Aligned() => TestHelper(false);

    [Fact]
    public void TestBattery_Unaligned() => TestHelper(true);

    private void TestHelper(bool unaligned)
    {
        // 128-bit key
        byte[] key = Enumerable.Range(0, 16).Select(x => (byte)x).ToArray();

        // SipHash initialized with the key
        SipHash prf = new SipHash(key);

        // Perform the test battery
        Span<byte> message = new byte[Vectors.Length + 1];
        if (unaligned)
        {
            message = message.Slice(1);
        }

        for (int i = 0; i < Vectors.Length; i++)
        {
            message[i] = (byte)i;

            // Compute the tag
            long actual = prf.Compute(message.Slice(0, i));

            // Get the target tag
            long expected = BitConverter.ToInt64(Vectors[i].Select(x => (byte)x).ToArray(), 0);

            if (expected != actual)
            {
                throw new Exception($"Test vector failed for {i:N}-byte message!");
            }
        }
    }
}
